Originally Posted by
Escape Velocity
The Alpha Vane warning light is part of the anti-ice system. It illuminates if the AOA heat malfunctions. It has no bearing on an actual AOA signal failure, only a failure of the vane heating system.
This sort of thing could be significant. If the Alpha vane had been knocked off in a birdstrike I wonder how long it takes to trigger an overheat if there is no vane left to dissipate it? You can bet someone has found out, and if that figure is close to 4min 12 sec it's an indication that might point to the alpha vane physical loss theorey.